The present invention relates to a packaging container for liquid contents, and comprising a casing and a top portion. The present invention also relates to a method of producing a packaging container for liquid contents, and comprising a casing and a top portion.
Beverage packages for drinks of different types, for example fruit juices, sports drinks or other non-carbonated drinks occur on the market in a plurality of different forms. Plastic packages, for example blow moulded bottles or deep drawn beakers or cans are common on the market. Packages of laminated paper/plastic laminate as well as deep drawn aluminium cans are also common. A cost-effective packaging container presupposes low production costs, high production output rates (mass production) and an expedient choice of materials. The material type(s) of the package should be selected such that the properties of the material are adapted not only to the beverage which is to be packed, but also to the package type and its use. The properties of the material as regards, for example, mechanical durability, liquid-tightness and gas barrier properties should, in other words, be selected such that the material combination as a whole is not over-qualified in relation to its purpose, which, for example, might probably be considered the case when a deep drawn aluminium can is employed for non-carbonated products, since its mechanical durability is greatly over dimensioned and the desired barrier properties can be obtained with but an extremely thin layer of aluminium, or other barrier material. Deep drawn plastic bottles are also normally over dimensioned from the point of view of mechanical strength in the packing of so-called still drinks, and it may generally be ascertained that it is usual that precisely still drinks are often packed in far too exclusive and expensive packaging containers.
An optimum packaging container which is particularly intended for still drinks and which is also sterilisable and thereby suitable for aseptic packing of drinks is made up of several parts, e.g. a casing, a top portion and a bottom portion, as well as a closure arrangement, each one of these being adapted to its given purpose in view of material selection and method of production. By utilising a separate top portion, this may, for example, be made from stronger or mechanically more stable material so that application and handling of the closure arrangement can take place without the risk of damage to the packaging container itself.
It is known in the art to produce packaging containers or parts therefor, for example top or bottom portions, from different types of plastic materials which are formed by various, per se known techniques for the forming of thermoplastic. The top portion often includes a closure arrangement or threads for screw caps, which increases the demands on production method and plastic quality for this particular part. For example, it is known to produce tops for packaging containers by injection moulding, which gives a high degree of accuracy and quality but impedes or renders impossible the production of tops with an integrated gas barrier layer, which, for example, is desirable in the packing of fruit juices. Another known forming technique is conventional thermoforming of web-shaped, heated material which may, in itself, include an integrated barrier layer. However, this method gives, in an unfavourable manner, varying material thicknesses and a poorer degree of accuracy for the various parts, which has a negative effect on the possibility of forming with sufficient precision a neck portion with threads or other mechanical engagement regions for a closure arrangement.
A further, per se known technique for producing packaging containers is blow moulding, in which process the starting material is preferably a freshly extruded plastic hose which, in itself may include an integrated barrier layer of a suitable, per se known barrier plastic. With the aid of mould halves surrounding the plastic hose, and suitable pressure difference, the plastic hose may be given the desired packaging configuration. As has been mentioned above, the packaging container may, in this instance, include a barrier layer, and the method also makes it possible to manufacture the packaging container with a high degree of accuracy also as regards, for instance, a threaded neck region, but the method suffers from the decisive drawback in the fact that it is comparatively slow, both in extrusion of the requisite hose length for realising the packaging container, and in the cooling of the packaging container formed from the hose, since the packaging container must remain in the mould halves until its temperature has fallen such that the material has become geometrically stable. The large and unevenly distributed plastic volume not only delays the cooling process, but also entails an uneven cooling effect and, since positive cooling in practice is not applicable, this method must be deemed far too slow for the modern, high capacity production of packaging containers.
Another prior art packaging container which is employed for packing, for instance, juices or other still drinks is the parallelepipedic packaging container which is produced by folding and thermosealing of laminated material, which includes layers of fibre, thermoplastic and, where applicable, also a barrier layer, for example aluminium foil. While this package may be produced in a rational and material-saving manner, it has limited forming possibilities, as well as reduced possibilities to be provided with a reclosable opening arrangement.
There is thus a general need in the packaging industry to realise a packaging container and a production technique that together make it possible to produce packaging containers for non-pressurized, so-called still, products, the packaging container offering a wide range of freedom of form and optimum material composition (which, when necessary, may include a barrier layer), and also makes it possible to produce packaging containers both rapidly and with great precision.
One object of the present invention is thus to realise a packaging container which possesses such material composition and make-up that it obviates the above-outlined drawbacks and obtains the desired properties both as regards mechanical strength, production accuracy and barrier capabilities.
A further object of the present invention is to realise a packaging container which, by an adapted choice of materials, reduces production time and material costs per unit to a minimum, without relinquishing any standards on stability and tightness.
Yet a further object of the present invention is to realise a packaging container which, in its entirety, includes layers of gas barrier material.
Still a further object of the present invention is to realise a packaging container which includes a top portion designed for cooperation with a closure arrangement.
The above and other objects have been attained according to the present invention in that a packaging container for liquid contents, comprising a casing and a top portion, has been given the characterizing feature that the casing includes a web-shaped multilayer material which is in the form of a sleeve provided with a liquid-tight longitudinal joint seam, the sleeve being, at its one end, connected to a bottom portion in liquid-tight fashion and, at its other end, is connected in liquid-tight fashion to the top portion produced from blow moulded thermoplastic material.
By designing the packaging container according to the invention in several parts in which each part has been given an optimum material composition, the packaging container will, as regards strength and tightness, be of optimum construction, at the same time as it is eminently suited for high capacity production.
There is also a general need in the art to realise a method of producing a packaging container, the method making it possible, in a rational manner and at high capacity, to produce packaging containers for still drinks.
Hence, the present invention further has for its object to realise a method of producing a packaging container, the method making it possible to produce a multi-part packaging container by separate, optimum production of the various parts and subsequent combining of the parts into a finished, liquid-tight packaging container.
Yet a further object of the present invention is to realise a method of producing a packaging container, the method making it possible rapidly and efficiently and with minimum material consumption, to produce complete packaging containers.
Still a further object of the present invention is to realise a method of producing a packaging container, the method being rapid and economical in terms of resources, and as a result, not suffering from the drawbacks inherent in prior art production methods, such as, for example, slow output rate, insufficient forming precision and high costs.
Yet a further object of the present invention is to realise a method of producing a packaging container which makes it possible to provide the packaging container in its entirety with a layer of gas barrier material.
The above and other objects have been attained according to the present invention in that a method of producing a packaging container for liquid contents, comprising a casing and a top portion, has been given the characterizing feature that the casing is formed by winding of web-shaped multilayer material to sleeve shape, whereafter the material edges are sealed to one another in a liquid-tight joint seam extending longitudinally of the sleeve, that the top portion is produced by a thermoplastic material being extruded for the formation of a hose which is subjected to a blow moulding operation and is divided into individual top portions, and that the sleeve and the top portion are connected to one another in liquid-tight fashion.
As a result of the method according to the invention, it will be possible to optimise the production of the different packaging container parts in respect of both material type, material strength and gas barrier properties, at the same time as production will be rational and operate at high output capacity.